Modern aero-engine development requires also a gradual increase in the overall effectiveness of lubrication systems. This particularly applies to bearing chambers where a complex two-phase flow is formed by the interaction of the sealing air and the lubrication oil. It is important to increase the level of understanding of the flow field inside the bearing chamber and to develop engineering tools in order to optimize its design and improve its performance. To achieve this, an experimental and a computational study of the whole front bearing chamber were carried out for a range of shaft rotational speeds and sealing air mass flow. The experimental measurements of the air velocity inside the chamber were carried out using a laser Doppler anemometer (LDA) in two-phase air/oil-flow conditions. The experimental facility is a 1:1 scale model of the front bearing chamber of an aero-engine. Computational 3D modeling of the bearing chamber was performed. The bearing gap and the presence of lubrication oil were modeled as an anisotropic porous medium with functions relating the pressure loss of the air coming through the gap and the tangential component of velocity of the air exiting the gap of the ball bearing with the air-flow rate through the gap and the rotational speed of the shaft. The methodology to obtain the above mentioned functions and the results of the detailed study are given (Aidarinis, J., and Goulas, A., 2014, “Enhanced CFD Modeling and LDA Measurements for the Air-Flow in an Aero Engine Front Bearing Chamber: Part II,” ASME Paper No. GT2014-26062). The enhanced computational model of the chamber implementing the law of pressure drop of the “lubricated” bearing and the function of modeling the tangential velocity of the air exiting the bearing was used to calculate the flow field for the full range of the measurements. A limiting curve dividing the operational map of the bearing chamber into two areas was predicted. Large vortical and swirling structures dominate the flow and they vary in size according to the position of the operation point relative to the limiting curve. Operation above the limiting curve leads to flow classified as type I with air going through the ball bearing while for operation below the limiting curve line the flow is classified as type II, there is no air-flow through the bearing gap.

References

References
1.
Wittig
,
S.
,
Glahn
,
A.
, and
Himmelsbach
,
J.
,
1994
, “
Influence of High Rotational Speeds on Heat Transfer and Oil Film Thickness in Aero-Engine Bearing Chambers
,”
ASME J. Eng. Gas Turbines Power
,
116
(
2
), pp.
395
401
.10.1115/1.2906833
2.
Glahn
,
A.
, and
Wittig
,
S.
,
1996
, “
Two-Phase Air/Oil-Flow in Aero Engine Bearing Chambers: Characterization of Oil Film Flows
,”
ASME J. Eng. Gas Turbines Power
,
118
(
3
), pp.
578
583
.10.1115/1.2816687
3.
Glahn
,
A.
,
Kurreck
,
M.
,
Willmann
,
M.
, and
Wittig
,
S.
,
1996
, “
Feasibility Study on Oil Droplet Flow Investigations Inside Aero Engine Bearing Chambers-PDPA Techniques in Combination With Numerical Approaches
,”
ASME J. Eng. Gas Turbines Power
,
118
(
4
), pp.
749
755
.10.1115/1.2816990
4.
Glahn
,
A.
,
Busam
,
S.
,
Blair
,
M. F.
,
Allard
,
K. L.
, and
Wittig
,
S.
,
2002
, “
Droplet Generation by Disintegration of Oil Films at the Rim of a Rotating Disk
,”
ASME J. Eng. Gas Turbines Power
,
124
(
1
), pp.
117
124
.10.1115/1.1400753
5.
Busam
,
S.
,
Glahn
,
A.
, and
Wittig
,
S.
,
2000
, “
Internal Bearing Chamber Wall Heat Transfer as a Function of Operating Conditions and Chamber Geometry
,”
ASME J. Eng. Gas Turbines Power
,
122
(
2
), pp.
314
320
.10.1115/1.483209
6.
Willenborg
,
K.
,
Busam
,
S.
,
Roßkamp
,
H.
, and
Wittig
,
S.
,
2002
, “
Experimental Studies of the Boundary Conditions Leading to Oil Fire in the Bearing Chamber and in the Secondary Air System of Aeroengines
,”
ASME
Paper No. GT2002-30241. 10.1115/GT2002-30241
7.
Gorse
,
P.
,
Willenborg
,
K.
,
Busam
,
S.
,
Ebner
,
J.
,
Dullenkopf
,
K.
, and
Wittig
,
S.
,
2003
, “
3D-LDA Measurements in an Aero-Engine Bearing Chamber
,”
ASME
Paper No. GT2003-38376. 10.1115/GT2003-38376
8.
Wang
,
Y.
,
Hibberd
,
S.
,
Simmons
,
K.
,
Eastwick
,
C.
, and
Care
,
I.
,
2001
, “
Application of CFD to Modelling Two-Phase Flow in a High-Speed Aero-Engine Transmission Chamber
,” ASME Fluids Engineering Division Summer Meeting, New Orleans, LA, May 29–June 1, Paper No. FEDSM2001-18167. 10.1115/FEDSM2001-18167
9.
Farrall
,
M.
,
Hibberd
,
S.
, and
Simmons
,
K.
,
2003
,
Modelling Oil Droplet/Film Interaction in an Aero-Engine Bearing Chamber
,
9th International Conference on Liquid Atomization and Spray Systems (ICLASS 2003)
,
Sorrento, Italy
, July 13–17.
10.
Farrall
,
M. B.
,
Hibberd
,
S.
, and
Simmons
,
K.
,
2000
, “
Computational Modelling of Two-Phase Air/Oil Flow Within an Aero-Engine Bearing Chamber
,”
ASME Fluids Engineering Division Summer Meeting
,
Boston, MA
, June 11–15, FEDSM2000-11081.
11.
Lee
,
C. W.
,
Palma
,
P. C.
,
Simmons
,
K.
, and
Pickering
,
S. J.
,
2005
, “
Comparison of Computational Fluid Dynamics and Particle Image Velocimetry Data for the Airflow in an Aeroengine Bearing Chamber
,”
ASME J. Eng. Gas Turbines Power
,
127
(
4
), pp.
697
703
.10.1115/1.1924635
12.
Gorse
,
P.
,
Dullenkopf
,
K.
, and
Bauer
,
H.-J.
,
2005
, “
The Effect of Airflow Across Aero-Engine Roller Bearing on Oil Droplet Generation
,”
17th International Symposium on Airbreathing Engines
, Munich, Germany, Sept. 4–9, ISABE-Paper No. 2005-1208.
13.
Flouros
,
M.
,
2005
, “
The Impact of Oil and Sealing Air Flow, Chamber Pressure, Rotor Speed, and Axial Load on the Power Consumption in an Aero-engine Bearing Chamber
,”
ASME J. Eng. Gas Turbines Power
,
127
(
1
), pp.
182
186
.10.1115/1.1805009
14.
Flouros
,
M.
,
2006
, “
Reduction of Power Losses in Bearing Chambers Using Porous Screens Surrounding the Ball Bearing
,”
ASME J. Eng. Gas Turbines Power
,
128
(
1
), pp.
178
182
.10.1115/1.1995769
15.
Gorse
,
P.
,
Dullenkopf
,
K.
,
Bauer
,
H.-J.
, and
Wittig
,
S.
,
2008
, “
An Experimental Study on Droplet Generation in Bearing Chambers Caused by Roller Bearings
,”
ASME
Paper No. GT2008-51281. 10.1115/GT2008-51281
16.
Hashmi
,
A.
,
Dullenkopf
,
K.
, and
Klingsporn
,
M.
,
2011
, “
Experimental Investigation of Lubrication Oil Film Dynamics in a Typical Aero-Engine Bearing Chamber Environment
,”
ASME
Paper No. GT2011-45545. 10.1115/GT2011-45545
17.
Aidarinis
,
J.
,
Missirlis
,
D.
,
Yakinthos
,
K.
, and
Goulas
,
A.
,
2011
, “
CFD Modeling and LDA Measurements for the Air-Flow in an Aero Engine Front Bearing Chamber
,”
ASME J. Eng. Gas Turbines Power
,
133
(
8
), p.
082504
.10.1115/1.4002830
18.
Morrison
,
G. L.
,
Johnson
,
M. C.
, and
Tatterson
,
G. B.
,
1991
, “
Three Dimensional Laser Anemometer Measurements in a Labyrinth Seal
,”
ASME J. Eng. Gas Turbines Power
,
113
(
1
), pp.
119
125
.10.1115/1.2906518
19.
Launder
,
B. E.
,
Reece
,
G. J.
, and
Rodi
,
W.
,
1975
, “
Progress in the Development of a Reynolds-Stress Turbulence Closure
,”
J. Fluid Mech.
,
68
(
3
), pp.
537
566
.10.1017/S0022112075001814
20.
ANSYS, 2010, ansys fluent 13.0 Documentation
, ANSYS Inc., Canonsburg, PA.
21.
Aidarinis
,
J.
, and
Goulas
,
A.
,
2014
, “
Enhanced CFD Modeling and LDA Measurements for the Air-Flow in an Aero Engine Front Bearing Chamber: Part II
,”
ASME
Paper No. GT2014-26062. 10.1115/GT2014-26062
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